A. Field of Invention
This invention generally relates to methods and apparatuses concerning pneumatic tires and more specifically to methods and apparatuses concerning a pneumatic tire having a tread with strips of tread base material having a higher stiffness property that extend into the tread cap material having a lower stiffness property.
B. Description of the Related Art
It is known to those of skill in the art that the overall performance of a pneumatic tire's tread pattern (including performance criteria such as wet handling, dry handling and stopping) may be compromised by the stiffness characteristics of the tread elements. Known methods of increasing the stiffness of a tread element include using relatively stiffer tread base materials and using relatively stiffer tread cap materials. These methods typically have the disadvantage, however, of compromising other tread performance criteria.
It is also known, as taught in International Publication No. WO 2005/063509, to provide a tire tread having sectors formed with a first material having a first modulus of elasticity and other sectors formed with a second material having a second modulus of elasticity. A problem with this method, however, is that the tire carcass must be moved sequentially from a first station where the first material is applied and then to a second station where the second material is applied. This method thus has disadvantages of increased complexity and increased cost.
What is needed is a method of increasing the stiffness characteristics of tire tread elements while minimizing the known disadvantages.